Containers in the context of the invention are containers or container-like packaging means of all kinds of the type used for packing products, e.g. beverages, foods, cosmetics, drugs etc. Containers in the context of the present invention therefore particularly include bottles, cans or other bottle-like or can-like containers made from very diverse materials, e.g. metal, glass or plastic, for example PET.
Container treatment machines and those comprising a rotary are particularly also known as labelling machines of very diverse construction. Inspection machines wherein the containers are for example, optically examined for damage and/or impurities are also known as rotary container treatment machines.
Known rotary container treatment machines comprise inter alia a carrousel or rotor which can be driven to rotate about a vertical machine axis, and which on at least one (first) rotor element configures a plurality of container carriers, for example in the form of container plates, which can e.g. be rotated or swivelled under control, and at least one further (second) rotor element permanently connected to the first rotor element and comprising a plurality of function elements e.g. in the form of clamping and/or centering elements each assigned to one container carrier, whereby the said elements can be displaced in a controlled manner by a cam on a section of a machine frame that does not rotate with the rotor (carrier element as lift cam carrier), for example are movable up and down through a predefined vertical lift, i.e. parallel to the machine axis.
Particularly when the container treatment machine is embodied as a labelling machine, the containers to be treated, i.e. labelled, are fed sequentially via a container inlet to the treatment stations or treatment positions each configured on the rotor of a container carrier and clamping and/or centering element (e.g. centering tulip), whereby the clamping and/or centering element concerned is lowered in a controlled way onto the top or head of a container at the moment when the container is transferred to a treatment position, such that for the treatment, the container is centered with its vertical container axis relative to the container carrier or the latter's axis and held clamped between the container carrier and the clamping and/or centering element. The containers are treated during the rotary motion within the angular range between the container inlet and the container outlet. At the container outlet, the clamping and/or centering element concerned is lifted off each container with the lifting cam and the container is then taken off or removed from the treatment position concerned.
With known container treatment machines the raising and lowering of the clamping and/or centering elements or centering tulips is effected by fixed-position curved paths or cams into which control rollers on the clamping and/or centering elements rotating with the rotor engage. When being clamped at the treatment position, each clamping and/or centering element is pressed on the container concerned by the force of a pre-tensioned spring with a closing force or head force which is determined inter alia by the spring constant of the compression springs which are used and by the container height such that a clamping force which is dependent on the container height is obtained, i.e. in particular a clamping force dependent on dimensional and manufacturing tolerances of the containers. The compression springs which are used, or their spring constants, are usually selected so that even containers with a low container height are clamped with force sufficient to securely hold these containers at the treatment positions even at high speed of the rotor and high angular accelerations and to press them against the respective container carrier with sufficient firmness.
During labelling and/or aligning or centering, each container is subjected inter alia to considerable angular accelerations and resulting acceleration forces which it can only withstand if pressed with sufficient force against the container carrier concerned. The container carriers are preferably rotatable or pivotable under control in order to respectively rotate or swivel the container concerned during the treatment, e.g. during labelling. For a reliable transmission of this controlled rotary motion to the container, the container carriers are preferably equipped with a friction lining, in addition to the quality of the friction lining the force by which the container is clamped between the clamping and/or centering element and the container carrier is essential for the reliable entrainment and rotary and swivelling motion of the container.